The overarching aim of the Family and Social Ecology Module (FSEM) is to prospectively elucidate the influences of family, peer and neighborhood environment, in relation to individual psychological phenotype and genotype, on the risk for substance use disorder (SLID) in early adulthood (age 19). This research module thus provides the data inputs pertaining to environment factors necessary for the Scientific Core to accomplish the three centerwide goals. The hypotheses to be tested in the FSEM in the next five years focus on the specific and conjoint impact of three environment domains (family, peers, neighborhood) on variation in individual liability (e.g., neurobehavior disinhibition) on substance use behavior and clinical SUD. Aim 1 is directed at elucidating the reciprocal influence of parenting practices and dyadic family relationships on the previously established association between parental SUD, deviant peer affiliations and child's substance use severity from ages 10-12, 12-14, 16 and 19. Aim 2 will identify the family, peer and neighborhood factors, including exposure to stressors, that moderate the relationship between neurobehavior disinhibition (ND) and level of substance use involvement across four timepoints of assessment (ages 10-12, 12-14, 16, 19). Aim 3 will delineate the factors in the environment (family, peers, neighborhood), in conjunction with ND phenotype, genotype and stressors that directly affect, mediate, or moderate the association between substance use and SUD across ages 10-12, 12-14, 16 and 19. Aim 4 is concerned with determining the role of quality of the family, peer, and neighborhood environments in the cross-generational transmissibility of substance use involvement. Thus, findings obtained from the FSEM will guide the development of contextually specific and developmentally appropriate prevention programs that effectively reduce the risk for developing SUDs.